The paper addresses some issues concerning routers for long-distance wireless mesh networks (LDWMNs) which are becoming increasingly popular in the last few years, above all to provide Internet access for small extra-urban communities. The paper discusses some main features of LDWMNs, the design challenges and the reasons behind the implementation choices. A router is described, based on a modular architecture which provides fault tolerance and guarantees gracefully degrading performances in case a fault occurs. One important feature of the router is the full-duplex capability of its wireless links which provides high throughput. Finally, the paper describes the implementation of the router using low-cost embedded components and addresses some issues concerning the management of the wireless links in the wireless mesh backbone.